The relationship between periodontal health and the restoration of teeth is intimate and inseparable. Maintenance of gingival health constitutes one of the keys for longevity of teeth and dental restoration. An adequate understanding of relationship between periodontal tissues and restorative dentistry is paramount to ensure adequate form, function, esthetics, and comfort of the dentition. Despite of an increased emphasis on the perio-restorative interface in restorative dentistry, many clinicians are unable to incorporate the concept of biologic width in a practical manner. This case report presents restorative management of subgingival caries by endodontal and minimally invasive periodontal treatment.

The dentogingival complex is composed of the gingival sulcus, the junctional epithelium, and the supra-alveolar connective tissue attachment. According to several authors, the integrity of this complex is important for the protection of the tooth supporting tissues, and therefore, the maintenance of periodontal health. [1] Caries, restorations, and dental fractures often invade the dentogingival junction, resulting in soft tissue inflammation and bone resorption, especially when they infringe the junctional epithelium and supracrestal connective tissue. In these cases, a periodontal surgical approach is often required to allow restorative procedures and to create a supra-alveolar area that accommodates the newly-formed biological width. [2] Supragingival margins facilitate impression making, provisional and definitive restorations and detection of secondary caries. In addition, some studies have demonstrated that subgingival restorations are associated with higher levels of gingival bleeding, attachment loss, and gingival recession than supragingival restorations. [3] The most commonly used techniques for biological width re-establishment are clinical crown lengthening surgery, orthodontic extrusion, or the association of both. The advantages of the above-mentioned surgical technique are the decreased duration of treatment and the reduced number of clinical sessions when compared to orthodontic extrusion. On the other hand, when compared to orthodontic extrusion, a greater amount of supporting bone removal is necessary. Although the orthodontic forced eruption preserves supporting bone and the adjacent soft tissues, the prolonged treatment time, and the need of a separate orthodontic apparatus may be limitations to the clinical use of this technique. [4]

Previous studies have suggested that a distance of 3-5 mm from the alveolar bone crest to the crown/restoration margin is required to accommodate the newly-formed supraosseous gingival complex and to permit proper restorations. [1],[5] In some cases, an odontoplasty may be a useful maneuver during the clinical crown lengthening surgery to create a smooth supra-alveolar area. [6] This approach enables the re- establishment of the dentogingival union at most favorable area with minimal bone removal.

Case Report

A 32-year-old female patient, attended Vishnu Dental College, Bhimavaram, had pain in upper front teeth region since 1 week. The patient had noticed the pain 1 week back, which was gradually increased in intensity. On examination, it was noticed that lingual pit caries was present on the maxillary left and right lateral incisors extending subgingivally [Figure 1]. No tenderness on percussion was felt, and 2 teeth were found to be vital when vitality test was performed. On radiographic examination, caries lesions were involved the coronal pulp [Figure 2]. Extraoral findings were absent. After thorough clinical and radiological examination, it was diagnosed as irreversible pulpitis of both maxillary lateral incisors, and it was decided to perform the treatment through interdisciplinary approach. Caries lesion was excavated; access cavity was made on both upper lateral incisors by using No. 2 round bur. The pulp was extirpated, and BMP was done. During the same appointment, obturation was done by lateral condensation technique. Later, fiber post was placed in the cavity and was restored with flowable composite resin [Figure 3] and [Figure 4]. After performing bone sounding, an envelope flap was planned to get the access for restoration of the subgingival caries on both lateral incisors. Sulcular and interdental incisions were placed by using No. 15 B.P blade from the distolingual side of the left maxillary canine to distolingual side of right maxillary canine without involving the midline lingual papilla after administering local anesthesia [Figure 5]. After reflection, it was noticed that the caries lesions on both the teeth were involved short of the crest of bone. Therefore, it was decided not to perform osteoplasty, and irrigation was done with povidone iodine 2% solution. GIC type IX was used to restore the cavities, and care was taken to merge the margins of the restoration with the surrounding tissues without any excess or sharp margins and was polished. 4 interrupted sutures placed [Figure 6] to close the flap, and postoperative instructions were given. Sutures were removed after 1 week, and the healing was satisfactory.

Caries, crown fractures, previous restorations, and shorter tooth preparations requiring additional retention will frequently dictate the placement of restoration margins beneath the gingival tissue crest. Restorative margin placement within the biologic width is detrimental to periodontal health and acts as a plaque retentive factor. When the restoration margin is placed too far below the gingival tissue crest, it will impinge on the gingival attachment apparatus, and a constant inflammation is created that may worse the patient's ability to clean this area. The more common finding with deep margin placement is that bone level appears to remain unchanged; however, gingival inflammation develops and persists on the tooth restored. [7] Investigators have correlated that subgingival restorations demonstrated more quantitative and qualitative changes in the micro flora, increased plaque index, gingival index, recession, pocket depth, and gingival fluid. [8] Hence, maintenance of gingival health constitutes one of the keys for tooth and dental restoration longevity. An adequate understanding of relationship between periodontal tissues and restorative dentistry is paramount to ensure adequate form, function and esthetics, and comfort of the dentition. Despite of an increased emphasis on the perio-restorative interface in restorative dentistry, many clinicians are unable to imply the concept of biologic width in a practical manner. [9] In our present case report, the caries lesions were involved short of the crest of alveolar bone, which couldn't be restored by placing gingival retraction cords. Hence, the gingiva was reflected from the distolingual aspect of the maxillary left canine to the distolingual aspect of the right maxillary canine to properly place the restoration subgingivally without violating the biologic width. This technique allows the clinician to restore the tooth with minimal invasive periodontal treatment, providing minimum discomfort to the patient, at the same time without violating the biologic width. This technique further prevents gingival recession unlike the conventional crown lengthening surgery, which needs an osteoplasty. After suture removal, the patient was followed for 1 month [Figure 7] and 6 months [Figure 8], and during the follow-up, it was noticed that the periodontal condition at the treated area was quite satisfactory.